The liver binding protein for alpha-tocopherol (vitamin E) was found to have high specificity for d-alpha-tocopherol when compared with several analogs. Hydrolysis studies showed that the protein is not a lipoprotein or nucleoprotein. Its presence in liver of six species of laboratory animals was demonstrated, but in no other tissue. Tocopherol bound to liver protein was no more effective as an antioxidant than free tocopherol. The nutritional selenium status of rat did not alter the amount or binding capacity of the protein. Investigation of factors that affect the exchange of alpha-tocopherol between red blood cells and plasma in vitro showed that the proportion of cells to plasma (hematocrit) and the concentration of total lipids in plasma both had marked effects. At low hematocrits, the concentration of tocopherol in red cells was increased while with high plasma lipids (constant hematocrit) the concentration of tocopherol in red cells was greatly reduced. BIBLIOGRAPHIC REFERENCES: Bieri, J.G., Evarts, R.P., and Thorp, S.: Factors Affecting the Exchange of Tocopherol Between Red Blood Cells and Plasma. Am. J. Clin. Nutr. 30: 686-690, 1977. Bieri, J.G., Stoewsand, B.S., Briggs, B.M., Phillips, R.W., Woodard, J.C., and Knapka, J.J.: Report of the Ad Hoc Committee on Standards for Nutritional Studies. J. Nutr. 107: 1977. (in press)